DESCRIPTION: The treatment of infants with antiepileptic medications after the resolution of neonatal seizures is controversial. Infants are commonly treated with Phenobarbital after their seizures have resolved even though data to support this practice is lacking. Exposure of the developing brain to Phenobarbital for prolonged periods may have deleterious consequences. The purpose of this application is to plan for a multi-center, randomized, controlled trial (RCT) to determine if continued treatment with phenobarbital for 4 months reduces seizure recurrence without adversely affecting neurodevelopmental outcome or if infants' outcomes are improved if no prophylactic medication is given. The goals for the planning phase of this RCT are (1) to establish clear definitions for inclusion/exclusion criteria and outcome measures; (2) to recruit a sufficient number of qualified centers to allow enrollment into the trial within a 2-3 year period; and (3) to develop tools to enhance recruitment and retention in the trial. Pilot studies will be done within the Planning Grant period to determine (1) the duration of neonatal seizures by video-EEG monitoring and (2) the standard of care with respect to diagnosis and treatment of neonatal seizures in participating centers. The trial itself will be conducted within the NICHD Neonatal Research Network centers, with additional non- Network centers recruited as needed. A Study Committee with be formed consisting of representatives of both Network and non-Network centers and, during the planning phase, will develop the Manual of Procedures for the proposed study. The personnel and resources of the Network will be available for consultation and collaboration during the planning phase, as well as for initiation and performance of the RCT.